The advised materials for the worm are hardened metal and bronze for the worm equipment. Nonetheless, based on the software, unhardened metal worms can run adequately and more economically on cast iron worm gears rated at 50%. In addition to steel and hardened steel, worms are obtainable in stainless metal, aluminum, bronze, and nylon worm gears are obtainable in steel, hardened metal, stainless metal, aluminum, nylon, and non-metallic (phenolic).